Leaf spring band construction



Oct. 16, 1951 v Q'DQNNELL' 2,571,475

LEAF SPRING BAND CONSTRUCTION Filed Dec. 1, 1945 1515 15 Z INVENTOR.

MICHA EL v O'Do N N Patented Oct. 16-, 1951 UNITED STATES PATENT OFFICEI 2,571,475 LEAF SPRING BAND CONSTRUCTION Michael v. O'Donnell,Pittsburgh, Pa., assignor to Crucible Steel Company of America, NewYork, N. Y-, a corporation of New Jersey Application December 1, 1945,Serial No. 632,161

1 Claim. 267-52) This invention relates to multi-leaf elliptic springsand the like, and more particularly to the leaf-retaining metal bandemployed at the center of such springs for containing the spring platesand holding them in position in integral assembly. The invention is animprovement on such spring bands as heretofore produced, and upon themethods heretofore employed for fabricating the same.

One object of the invention is to provide a stronger spring band thanheretofore, and one which is free from the forging strains and crackssuch as are frequently encountered in such bands as made by priormethods.

Another object of the invention is to provide a spring band which caneasily be adapted to fit the requirements of a number of springs ofdifferent designs. In accordance with this objective, the inventionprovides a spring band construction and method of fabrication, whereby aspring band may be produced in a size adapted to suit the greatestdimension of a group of springs of various sizes, and capable of beingeasily adapted to fit the smaller sizes in the group.

Spring bands, especially those employed for the elliptic springs used inrailway car and locomotive constructions, serve two purposes: First,they contain and hold the superimposed spring plates in proper positionin integral assembly; and, secondly, one end of the spring band, incontacting the spring seat, transmits the spring load to the spring seatand takes the Wear due to this contact. Because of this, the end of thespring band which contacts the spring seat is always made of a greaterthickness and weight of material than is the other end and the twoelongated sides of the band. How much greater this thickness is dependsto some extent on the judgment of the designer of the spring and also onthe thickness of the spring seat. For this reason, spring bands asdesigned by different desi ners to contain the same number of springplates of the same size, may vary in thickness of the end of the bandcontacting the spring seat. This makes it necessary for the springmanufacturer to produce such spring bands in small quantities to suitthe individual requirements of each purchaser.

In accordance with the practices heretofore in vogue, such spring bandshave ordinarily been produced, by starting with a flat, rectangularsteel plate, having a thickness equal to the thick end of the finishedband. and other dimensions as required by the size of the finishedarticle. The spring band is produced from this flat plate by forg t ppsite ends thereof to the thickness required by the sides and oppositethinner end of the band, leaving, however, the central portion of theplate unforged up to a width corresponding to the thick end of thefinished band. The forged ends are now bent downwardly at right anglesto the thickened central section, and the ends thereof are curledinwardly toward each other until they contact, whereupon the curled endsare squared off and the contacting edges welded together to provide thedesired open-ended, rectangular contour of the finished band. The abovemanufacturing steps are carried out under a forging hammer, whichimposes severe forging strains in the metal, and often produces cracksand fissures in the metal, particularly in the regions where the forgedends are bent at right angles to the thickened central por-- tion.Moreover, the band as thus produced is suited for a spring of but onedesign.

In contrast with the prior practice of making spring bands as outlinedabove, the process-0i the present invention starts with a flat,rectangular metal plate having a substantially uniform thicknesscorresponding to the thinner sides and end of the finished band, theother dimensions of the plate, i. e., width and length, being selectedto produce a resulting band of desired dimensions. This fiat plate isthereupon press-formed into a substantially rectangular tubularconfiguration, coniorming in length and width to the finished band, andwith the opposite ends of the metal plate abutting each other along themedian line of one of the ends of the so-formed rectangular member. Arectangular plate having a thickness preselected as noted below, and awidth and length corresponding to the aperture width and length of therectangular tubular member, is now inserted therein in overlappingrelation to the aforesaid abutting ends, whereupon this plate is weldedin position and at the same time the butting ends of the rectangularmember are welded together.

The plate thus inserted and welded in position is referred to herein asa filler plate and serves, in one of its functions, to impart to one endof the resulting spring band the additional thickness required forwear-resisting and loadcarrying purposes above stated. Also, it servesto strengthen and reinforce the end of the resulting band which containsthe weld seam of the originally abutting ends.

In accordance with a feature of the invention as above noted, therectangular spring band member can be made of a width and length toaccommodate a number of different spring designs,

56 wherein the leaf springs, although of the same width, vary in number,or in aggregate sectional length in the vertical direction, thedifferences between this dimension and the aperture length of the springband being accommodated by employing filler plates of differentthicknesses to fill up any space remaining between the leaf assembly andthe spring band.

By employing the spring band construction and method of fabricationabove outlined, no abnormal stresses are imposed by the press-formingoperation, resulting in a spring band which is considerably stronger forgiven dimensions than is obtainable under prior practices.

Referring now to the annexed drawing:

- Fig. 1 is a vertical elevation, shown more or less diagrammatically,of a part of a locomotive assembly showing an elliptic spring mounted inoperative position, with its spring band resting on the spring seat;while Fig. 2 is a section at 22 of Fig. 1.

Figs. 3 to 7 inclusive are perspective views illustrating the successivesteps employed in producing a spring band in accordance with thisinvention; Fig. 3 showing the flat metal plate of requisite dimensionsused as the starting material; while Figs. 4 and 5 illustrate theresults of the successive press-forming operations employed forconverting the flat plate of Fig. 3 into the substantially rectangulartubular member above referred to. Fig.0 shows the filler plate, and Fig.7 the completed spring band comprising the Fig. 5 construction with thefiller plate incorporated therein.

Referring for the moment more particularly to, Figs. 1 and 2, there isshown a portion of a locomotive truck I supported on a car wheel 2,

the truck in turn mounting a spring seat 3, on which rests the thickenedend I of a spring band I of an elliptic spring shown generally at 8, andcomprising a stack of superimposed spring plates 1, retained in integralassembly within the spring band 5. A body portion of the locomotive tobe resiliently supported (and not shown because no part of theinvention) is secured to a member I fulcrumed, as at 9, to one end ofthe elliptic spring 6, the opposite end of the spring being fulcrumed,as at ID, to one end of a tie rod ii, the opposite end of which ispin-connected, as at II, to the truck I.

Referring more particularly to Figs. 3 to 7 inclusive, the spring band 5of Figs. 1 and 2 is constructed as follows: A rectangular steel plateIt, Fig. 3, of the required length and width, and of the thicknessindicated at H, Fig. 2, is initially press-formed to the configurationshown in Fig. 4 wherein the opposite ends l5, ii of the plate I! arebent downwardly, at right angles to the body portion of the plate, asindicated at I 5 and II in Fig. 4. The Fig. 4 construction is againpressformed to the substantially rectangular tubular form shown in Fig.5, comprising the upper end l1, side walls It and I9, and lower endconsisting of the abutting end portions l5 and IS. A filler plate 29,Fig. 6, having the desired thickness as aforesaid, and a width andlength corresponding to the width and length of the aperture 2|, Fig. 5,ofthe rectangular member, is thereupon disposed within the rectangularmember in'overlapping relation to the abutting ends Ii, ll, asillustrated in Fig. 7. Thereupon, the filler plate 20 is welded in placeas shown in Fig. 7, and at the same time the abutting ends ii, I. of therectangular member are welded together as indicated at 22 to provide thefinished spring band.

As above stated, the vertical height of the rectangular member, Fig. 5,may be made such as to accommodate a series of leaf spring designs ofdiilferent sizes, the individual spring plates of which have the samewidth, but vary in number or in thickness in superimposed assembly, inwhich event the thickness of the filler plate 2| is so chosen as to takeup whatever space remains in a particular design, between the aggregateheight of the leaf spring assembly and the aperture height of therectangular member, Fig. 5. In this way, and by employing filler platesof various thicknesses, the same spring band design may be employed forthe various spring designs referred to.

I claim:

A'spring band for retaining a stack of spring plates in integralassembly, comprising a substantially rectangular tubular memberconsisting of a rectangular metal strip of uniform thickness,

, shaped into said tubular contour with the opposite edges of said stripbutt welded together, a metal filler plate of uniform thickness disposedwithin said tubular member and spanning the full aperture width thereofand extending the full length thereof in overlapping relation to saidbutt weld, said plate being welded to said tubular member, and saidplate being of a thickness preselected to provide a resulting inneraperture of said tubular member conforming substantially incross-section to the cross-section of the spring plate assembly to beretained therein.

- MICHAEL V. O'DONNELL.

REFERENCES crrEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,581,916 Broussouse Apr. 20,1926 2,095,585 Yates Oct. 12, 1937 FOREIGN PATENTS Number Country Date470,066 Great Britain Aug. 3,1937

OTHER REFERENCES Laminated Springs by T. H. Sanders, Bpon andChamberlain, 123 Liberty St., New York, pages 478, 479 and 490. (Copy inDiv. '45.)

The Welding Encyclopedia, 9th edition, edited by S. Plumley, The WeldingEngineer Publishing Co., 608, S. Dearborn St., Chicago, Ill., page 481,Figure H. (Copy in Division 14.)

